 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.console.actions;


 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.text.ITextOperationTarget;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.ui.texteditor.IUpdate;

 /**
  * Common function for actions that operate on a text viewer.
  * <p>
  * Clients may subclass this class.
  * </p>
  * @since 3.0
  */
 public class TextViewerAction extends Action implements IUpdate {

     private int fOperationCode= -1;
     private ITextOperationTarget fOperationTarget;

     /**
      * Constructs a new action in the given text viewer with
      * the specified operation code.
      *
      * @param viewer
      * @param operationCode
      */
     public TextViewerAction(ITextViewer viewer, int operationCode) {
         fOperationCode= operationCode;
         fOperationTarget= viewer.getTextOperationTarget();
         update();
     }

     /* (non-Javadoc)
      * @see org.eclipse.ui.texteditor.IUpdate#update()
      *
      * Updates the enabled state of the action.
      * Fires a property change if the enabled state changes.
      *
      * @see org.eclipse.jface.action.Action#firePropertyChange(String, Object, Object)
      */
     public void update() {

         boolean wasEnabled= isEnabled();
         boolean isEnabled= (fOperationTarget != null && fOperationTarget.canDoOperation(fOperationCode));
         setEnabled(isEnabled);

         if (wasEnabled != isEnabled) {
             firePropertyChange(ENABLED, wasEnabled ? Boolean.TRUE : Boolean.FALSE, isEnabled ? Boolean.TRUE : Boolean.FALSE);
         }
     }
     
     /* (non-Javadoc)
      * @see org.eclipse.jface.action.IAction#run()
      */
     public void run() {
         if (fOperationCode != -1 && fOperationTarget != null) {
             fOperationTarget.doOperation(fOperationCode);
         }
     }
     
     /**
      * Configures this action with a label, tool tip, and description.
      *
      * @param text action label
      * @param toolTipText action tool tip
      * @param description action description
      */
     public void configureAction(String text, String toolTipText, String description) {
         setText(text);
         setToolTipText(toolTipText);
         setDescription(description);
     }
 }

